Ultrafast Fluorescence Signals from β-Dihydronicotinamide Adenine Dinucleotide: Resonant Energy Transfer in the Folded and Unfolded Forms.,The Journal of Physical Chemistry B

当前位置： X-MOL 学术 › J. Phys. Chem. B › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Ultrafast Fluorescence Signals from β-Dihydronicotinamide Adenine Dinucleotide: Resonant Energy Transfer in the Folded and Unfolded Forms.
The Journal of Physical Chemistry B ( IF 2.8 ) Pub Date : 2020-01-08 , DOI: 10.1021/acs.jpcb.9b10012
Andrea Cadena-Caicedo ₁ , Beatriz Gonzalez-Cano ₁ , Rafael López-Arteaga ₁ , Nuria Esturau-Escofet ₁ , Jorge Peon ₁

Affiliation

β-Dihydronicotinamide adenine dinucleotide (NADH) plays a critical role in biological redox processes. Inside the cell, NADH can be in a folded or an unfolded conformation, depending on the chemical environment that surrounds it. It is known that selective excitation of adenine in NADH can induce energy transfer events from this nucleotide to the reduced nicotinamide chromophore. From the anticipated time scales, this process must compete with adenine's internal conversion channel, which is known to occur in the sub-picosecond time scale. In this work, we studied the dynamics of the excited states of both chromophores in NADH through the time resolution of the spontaneous emission from both nucleotides. Through these experiments, we extend the knowledge about the competition between the different photophysical channels both in the folded and unfolded states. The study involved the folded and unfolded states of NADH by experiments in water and methanol solutions. Our femtosecond fluorescence results were complemented by the first nuclear magnetic resonance through space magnetization transfer measurements on NADH, which establish the solvent-dependent folded versus unfolded states. We determined the dynamics of the excited states by direct excitation of dihydronicotinamide at 380 nm and adenine at 266 nm. From this, we were able to measure for the folded state, a time constant of 90 fs for energy transfer. Additionally, we determined that even in what is referred to as an unfolded state in methanol, non-negligible excitation transfer events do take place. Spontaneous emission anisotropy measurements were used in order to confirm the presence of a minor energy transfer channel in the methanol solutions where the unfolded state dominates.

中文翻译：

来自β-二氢烟碱酰胺腺嘌呤二核苷酸的超快荧光信号：折叠和展开形式的共振能量转移。

β-二氢烟碱酰胺腺嘌呤二核苷酸（NADH）在生物氧化还原过程中起着至关重要的作用。在细胞内部，NADH可以处于折叠状态或展开状态，具体取决于周围的化学环境。已知在NADH中腺嘌呤的选择性激发可以诱导能量从该核苷酸转移到还原的烟酰胺发色团上。从预期的时标来看，该过程必须与腺嘌呤的内部转化通道竞争，众所周知，腺嘌呤的内部转化通道发生在皮秒以下的时标中。在这项工作中，我们通过时间分辨两个核苷酸自发发射的时间，研究了NADH中两个生色团的激发态的动力学。通过这些实验，我们扩展了关于在折叠和展开状态下不同光物理通道之间竞争的知识。通过在水和甲醇溶液中进行的实验，研究涉及到了NADH的折叠和未折叠状态。通过在NADH上进行空间磁化转移测量，我们的飞秒荧光结果得到了第一次核磁共振的补充，这建立了溶剂依赖性的折叠状态与未折叠状态。我们通过在380 nm处二氢烟酰胺和在266 nm处腺嘌呤的直接激发来确定激发态的动力学。由此，我们能够测量折叠状态，能量传递的时间常数为90 fs。此外，我们确定，即使在甲醇中被称为未折叠状态的情况下，也会发生不可忽略的激发转移事件。

更新日期：2020-01-09

点击分享查看原文

点击收藏

阅读更多本刊最新论文